The difference between precipitated calcium carbonate and activated calcium carbonate
The particle shape of precipitated calcium carbonate is relatively regular and can be regarded as monodisperse powder. Its particle size can be made very fine, such as ultra-fine calcium, micro-fine calcium, nano-calcium, etc. Precipitated calcium carbonate generally has high whiteness, with a standard usually above 90, and a high sedimentation volume, generally above 2.5. Its average particle size is generally 1-3 microns, and the particle size distribution is relatively narrow.
Precipitated calcium carbonate is produced through chemical methods. The production process involves calcining raw materials such as limestone to generate lime and carbon dioxide, then adding water to digest the lime to produce calcium hydroxide lotion, and subsequently introducing carbon dioxide for carbonation reaction to form calcium carbonate precipitate. This precipitate is then dehydrated, dried, and crushed to obtain the precipitated calcium carbonate product.
Precipitated calcium carbonate plays a significant role in various fields due to its characteristics such as high whiteness, high purity, high scattering coefficient, and stable pH value. Specifically, it is commonly used as:
Fillers and thickeners: In rubber, plastic, and coatings, precipitated calcium carbonate serves as a filler, which can reduce costs, lighten the weight of materials, and simultaneously enhance the hardness and wear resistance of products. In food and pharmaceuticals, it can also function as a thickener, increasing the viscosity and consistency of products.
Coating agent and filter material in the paper industry: In the papermaking process, precipitated calcium carbonate can serve as a coating agent and filter material, enhancing the hardness and opacity of paper while reducing papermaking costs.
Feed additive: In feed, precipitated calcium carbonate can provide the calcium and phosphorus required by animals, which is conducive to their growth and development.
Pharmaceutical and oral care products: In the pharmaceutical field, precipitated calcium carbonate can serve as a calcium supplement to prevent and treat osteoporosis. Additionally, it can be utilized in the production of oral care products such as toothpaste and chewing gum, as well as orthopedic medical materials like artificial bones and dental filling materials.
Additives in the construction field: In the construction industry, precipitated calcium carbonate can be used as an additive in building materials, such as in the production of lightweight concrete and insulation materials. It can reduce the density of building materials, enhance their insulation performance, and lower the cost of construction materials.
Properties and applications of activated calcium carbonate
The particle shape of activated calcium carbonate is irregular, belonging to a polydisperse powder with a wide particle size distribution, typically ranging from 5 to 10 micrometers in average diameter. Due to the activation process, its surface properties have been improved, exhibiting strong hydrophobicity, high whiteness, good fluidity, and uniform dispersion.
Activated calcium carbonate is primarily produced through physical methods. Its production process typically involves using high-purity limestone (such as calcite, chalk, etc.) as the raw material and refining it through physical means such as grinding. On the surface of the ground calcium carbonate particles, an activator (such as phthalate coupling agent, stearic acid, lignin, etc.) is added for surface treatment, forming a special coating structure on the surface to enhance its dispersibility and affinity in the polymer matrix.
The uses of activated calcium carbonate
With its excellent dispersibility and affinity, it has demonstrated extensive application value in multiple industrial fields. Specifically, it is often used as:
High-grade filler: In industries such as rubber, plastics, plastic-steel doors and windows, PVC cable materials, pipes, tires, shoe soles, polyethylene blown films, sealing rubber strips, fiberglass products, and cable packaging cloth, activated calcium carbonate serves as a filler. It not only increases the volume of products and reduces costs but also significantly enhances the dimensional stability, hardness, and rigidity of the products, improving processing performance and heat resistance.
Fillers and coating agents in the paper industry: In the papermaking process, activated calcium carbonate can serve as a filler and coating agent, improving the glossiness of paper, enhancing its hardness, and making it more durable.
Physical pigments in the coatings industry: In coatings, activated calcium carbonate serves as a filler, functioning as a structural backbone to enhance the wear resistance, corrosion resistance, and glossiness of the coatings. Additionally, it reduces the viscosity of the coatings, increases the solid content, lowers the baking temperature, and shortens the baking time, thereby improving the production efficiency and product quality of the coatings.
Dispersant and stabilizer in the ink industry: In ink, the dispersibility and stability of activated calcium carbonate contribute to enhancing the printing effect and glossiness of the ink.
